Operational pressures on maintenance engineers likely resulted in an error that saw a Jetstar Airbus A320 land in Sydney last September with its thrust reversers deactivated, an investigation has found.
A lock-out pin was not removed when engineers at the Qantas maintenance facility in Brisbane were working on the plane
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The pilots of the Jetstar flight were unaware that the thrust reversers were inoperative until they tried to use them after the plane landed in Sydney. Thrust reversers help slow the plane during the landing roll by redirecting the thrust from the engines.
The captain of the flight from Brisbane called “no reverse” and the first officer completed the landing using normal braking. There was no damage to the aircraft or injuries to the 184 passengers and crew.
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The captain later recalled that pre-flight checks had not revealed any indications that the thrust reversers were de-activated.
Australian Transport Safety Bureau investigators later found a maintenance team had deviated from procedures, probably due to operational pressure.
Prior to the incident, the aircraft had undergone a three-day maintenance check during which engineers identified that the horizontal stabilizer actuator required replacement.
This added a half day of work to the schedule and to recover the lost time, the team was brought in to start work at 4 am the next day.
Adding to the pressure was the fact the aircraft departure time was brought forward, and the engineers were instructed to complete the maintenance by the end of first shift.
Many worked through their lunch breaks to ensure they could complete the maintenance on time, with some later reporting they were feeling tired and felt a responsibility and pressure to finish the work on time.
The thrust reversers needed to be deactivated so the engineers could perform engine leak tests.
To save time, they used a lock-out pin that did not have required “remove before flight” warning flags on them. They also did not put additional notices in the cockpit warning the thrust reversers were deactivated.
This meant the installed pins were missed after the engine leak test and the engine cowlings were closed with them still in place.
“While working under the compressed schedule, engineers deviated from the written procedures, and the incorrect lockout pin was installed and then not removed later,’’ the ATSB said.
“As a result, the aircraft was returned to service with the thrust reverser system inadvertently deactivated.”
Qantas conducted an internal review and said the engineers were working in compliance with an approved fatigue management framework but said awareness of certain safety precautions “was not as robust as it should be”.
The company took a number of actions as a result of the incident which included issuing an alert to staff, discussions with Jetstar aircraft-certifying staff and review of lockout pin management in Brisbane to ensure there were no systemic problems.
The ATSB said the safety message from the investigation was that functional checks were the last line of defense in maintenance work.
“Failure to follow procedures, such as functional checks, can result in unintended consequences,’’ it said. “Additionally, it is imperative that aircraft maintenance engineers feel empowered to stop a process when they observe procedural violations or foresee that an error is likely to occur.”
